A popular feature of modern telecommunications systems is “call waiting.” Without call waiting, a person who was engaged in a telephone call with a second person did not know when a third person was calling him or her. In contrast, with call waiting, a person who is engaged in a telephone call does, in fact, know when a third party is calling.
In accordance with a typical call waiting system, the telecommunications system notifies the first person that a third person is calling by injecting a series of beeps into his or her ear. This is accomplished by generating and injecting the beeps into the audio channel from the second person. Upon hearing the beeps, the first person can either ignore the incoming call or can put the current call on hold and switch to the incoming call.
Although call waiting is popular and convenient, the method of notification is disadvantageous in that it often drowns out the voice of the second person. This is intrusive and disruptive and somewhat eliminates the overall advantage of call waiting in the first place.
Therefore, the need exists for a less intrusive and disruptive technique for notifying a person who is engaged in a telephone call with a second person that a third person is calling him or her.